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No. 456,517. Patented July 21, 1891.

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P MARLEY ORB ROASTING FURNAGE.

No. 456,517. Patented July Z1, 1891.

UNITED STATES PATENT OFFICE.

-PATRICK MARLEY, OF IDAHO CITY, IDAI'IO, ASSIGNOR OF ONE-HALF TO GEORGEII. ROBERTS AND J. H. RICHARDS.

ORE-RoAsTlNe FURNACE.

SPECIFICATION forming part of Letters Patent No. 456,517, dated July 21,1891.

Application filed October 4, 1890. Serial No. 367,053. (No model.)

To @ZZ whom, it may concern.-

.Be it known that I, PATRICK MARLEY, a citizen of the United States ofAmerica. residing at Idaho City, in the county of Boise and State ofIdaho, have invented certain new and useful Improvements inOre-Roasting' Furnaces, of which the following is a specification,reference being had therein to the accompanying drawings.

The object of my inventionis to provide apparatus for treatingrefractory auriferous and argentiferous ores, such as are found to existgenerally in the western part of the'United States, whereby the gold andsilver will be thoroughly and cheaply separated from the base metals bygradually-applied heat when gold only is found in paying quantities andby such heat and the use of asmall quantity of common salt when silveris found combined with the gold-bearing ore in sufficient quantity towarrant saving. I attain this object by the means hereinafter set forth,and carry my process into practical application by the use of themechanical device shown in the drawings, wherein-- Figure l is aperspective View of my primary reducing-furnace- Fig. 2 is alongitudinal section of the same. Fig. 3 is a perspective view of mysecondary reducing-furnace, and Fig. Ai. is a longitudinal section ofthe same.

Like letters refer to similar parts throughout the several views.

The reducing-furnaces consist of a series of inclosed horizontalstationary beds or platforms of suitable dimensions, rising one slightlyabove the other as they recede from the iirebox, designated in thedrawings a, b, c, d, e, and f, each furnace having a bifurcated iiue g,the flue upon the primary reducing-furnace having attached on its underside beyond the point of juncture of the legs thereof aquicksilver-arrester h, having 1n eans of relieving it of itsaccumulations in valves t' and 7s, which serves to arrest the escape ofquicksilver when partly-amalgamated ore is being worked and 'preventsthe salivation of operatives. The fire-box Z and ash-pit m are of theusual construction, the fire-box cornmunicating directly with thehorizontal stationary beds or platforms. Feeding-funnels 'n and n forthe purpose of charging the furnaces are located at the end most remotefrom the {ire-box. For convenience in handling the charge the horizontalstationary beds or platforms should be about eightfeet wide and ten feetlong.

rlhe top ofthe primary reducing-furnace is removable for the purpose ofregulating the heat, and may be constructed of sheetiron. For thepurpose of further means of regulating the heat I provide dampers p p ineach leg of the iiues in both furnaces.

To facilitate the manipulation of the ore on the beds, doors r areprovided opposite each horizontal bed, and for the purpose of inspectionand manipulation of the ore in the secondary reducing-furnace I providethe peephole s in the end thereof.

The body ofthe furnaces may beconstrueted of brick or other suitablematerial, the beds presenting smooth surfaces.

I have found the mechanical device herein described best adapted tocarrying my process into effective operation.

In carrying out my process I take the ore, either wet or dry, from thecrusher and charge the horizontal bed a therewith, spreading thepartly-comminuted ore evenly over the surface of the bed to a depth ofabout six inches. I subject the charge to a moderate heat for about twohours, the heat passing over the ore from the iirebox. It is importantthat the heat be evenly distributed throughout the iireeboxes `of bothfurnaces, and for that reason I prefer to employ wood as fuel, outapproximately in lengths equal to the depth of the [irc-box. During the'time the ore remains on bed a I stir it twice. At the expiration of twohours I move the charge on horizontal bed a to horizontal bed i), nextthe fire-box, where I again spread it evenly and subject it to theaction of the fire for about the same period and in the same manner asin horizontal bed a, stirring two or three times. On removal of chargefrom horizontal bed a I recharge that bed, as in the first instance,with ore from the Crusher and proceed therewith as before. It isimportant to maintain a sufficiently low degreeof heat in the primaryIOC obviated. At the expiration of about two hours, as heretofore setforth, I draw the Charge from horizontal bar b through opening 'ortwice.

t, prepared for that purpose, and while the ore is hot I transfer it tohorizontal bed c in the secondary reducing-furnace through the funnel orchute n of that furnace, Fig. 4, spreading the ore evenly over thesurface of the bed, as in the primary furnace. The ore is here subjectedto a much higher degree of heat than in the primary reducing-furnace. Itshould occupy this bed about two hours, during Which time it should bestirred once At the expiration of the time specied the ore on bed cshould be moved to bed d, where it is subjected tothe same treatment andpermitted to remain for the same period ason bed c. Itis then removed tohorizontal bed e, which it should occupy about two hours, during whichtime it should be stirred three times. n Then it should be removed tobed f, which it should also occupy about two hours, during which time itshould be stirred four or tive times. It will be not-iced that thecharge of ore receives substantially the same treatment on eachsuccessive stationary horizontal bed, except that on the two beds lastoccupied e and f the process of stirring is more frequent than upon thepreceding beds. As the fire-box is approached, the heat becomes moreintense. As each bed is relieved of its charge by transfer toward thefire-box or'its removal from Vthe furnace, the bed so relieved isoccupied by the charge immediately following, the bed a beingsuccessively charged when relieved by ore from the crusher, as abovestated. It will be thus seen that it requires about twelve hours for asin-4 gle charge to pass over all the beds and that the heat beinguniform in the respective furnaces the charge undergoes a gradualincrease of heat from the time it enters on stationary horizontal bed auntil the highest degree of heat is reached on stationary horizontal bedf. A high degree of heat should be maintained at stationary horizontalbed f in the secondary furnace-say about 400O Fahrenheit. After thecharge has passed over each stationaryhorizontal bed and been subjectedto heat as described and remained the required two hours on bed f, Idraw the charge through opening n, Fig. 2l, and allow itto cool. Vhencool, it is prepared to bc subjected to Concentration by being passedthrough any approved dry concentrator.

If silver is combined with gold in the ore in sufficient quantity tojustify saving the silver, I use from one to tive percent. of commonsalt to convert the silver present into a chloride, mixing the salt withthe ore on introducing the ore into the primary reducingfurnace, but nototherwise varying the process herein described.

I am well aware that salt has been used before to assist in reducingrefractory metals contained in gold and silver bearing ores; but by' myprocess I am enabled to wholly dispense with salt or any other chemicalin working ores bearing gold only in paying quantities, and insilver-bearing ores combined with gold, where it is desirable to savethe silver, I use but a small quantity of salt, as heretofore stated.

In the drawings but two'beds are shown in the primary furnace and fourbeds in the secondary furnace. More beds may be used in carrying out myprocess; but the time consumed on each bed should be reduced iuproportion to the increased number of beds employed.

I-Iaving thus described my invention, what I claim, and desire to secureby Letters Patent, is-

In a furnace having a fire-grate with removable top and stepped hearths,an outlettlue having two branches leading from the furnace-chamber atthe end remote from the grate to a common conduit, valves arranged oneach branch of the flue, and a mercuryarresting pan arranged in the wallof the conduit near the branch of the flues, having a valve and draw-offpipe, as and for the purposes described.

In testimony whereof I affix my signature in V presence of twowitnesses.

PATRICK MARLEY. Vtnesses:

Jos. VosHAv, JAMES W. WHITE.

